GST filing in Singapore: how to complete and submit the GST F5

IRAS gives one month to file a GST F5 and does not grant extensions, on the stated view that a month is reasonable. For a bookkeeper with a dozen clients on the same quarter, a month is tight, and the only way to make it comfortable is to arrive at quarter end with the coding already right. This guide follows a single return from closing the period to submission, then covers what IRAS itself lists as the commonest errors, the penalties for filing late, and the rules on when a mistake can be fixed in the next return and when it needs a GST F7. The underlying GST rules are in the Singapore GST guide. Every figure links to IRAS in the Sources section.

Get access first

IRAS digital services in the myTax Portal business account require authorisation through Corppass. A business grants its employees and third parties, such as tax intermediaries, access to specific services, and GST filing is one of them ^[1] . If you file for clients, have each one authorise you for GST filing at onboarding, not in the last week of the month. See the client onboarding checklist.

Close the period

• Reconcile every bank and card account to the last day of the accounting period.
• Enter every sales invoice and every purchase supported by a tax invoice.
• Revalue or convert foreign currency transactions on the basis the client uses consistently.
• Clear uncoded transactions. Without a tax code they cannot land in the right box.

Review the coding against IRAS’s own error list

IRAS publishes the errors it finds most often. Use them as the review checklist ^[2] .

• Input tax claimed without a tax invoice, or on disallowed expenses. All input tax claimed must be supported by valid tax invoices addressed to the business, or simplified tax invoices. Motor car expenses, medical expenses, and private expenses such as family trips and personal mobile subscriptions are not claimable.
• Zero-rating because the customer is overseas. Goods cannot be zero-rated unless export is certain at the time of supply and the export documents are held. Services qualify only if they meet the criteria for an international service.
• No GST accounted for on gifts. GST is due on gifts exceeding $200 where input tax on them has been claimed.
• No GST on business assets sold. The sale of office furniture, equipment, machinery, and commercial property is chargeable even though the assets are not trading stock.

Add the checks every jurisdiction needs: one supplier coded two ways, exempt items sitting in zero-rated, and overseas services that should be under reverse charge.

The boxes

The GST F5 box titles, as IRAS lists them ^[2] :

For a typical local business the working boxes are 1 to 8 and 13, with “No” for the questions in 10 to 12 and 14 to 17. Boxes 1 to 5 are values excluding GST; boxes 6 and 7 are the tax.

Test the figures

• Box 6 against Box 1. Output tax should be 9% of standard-rated supplies. A difference means a supply is in the wrong box or a rate is wrong.
• Box 7 against Box 5. Input tax will be below 9% of taxable purchases where zero-rated purchases or blocked claims are involved. Compare the ratio with the last few returns.
• Box 4 against the profit and loss. Total supplies should reconcile to income for the period, with differences listed.
• Box 13 against the accounts. Revenue is the business’s main income, reported for information.
• Box 8 against the ledger. After posting, the GST accounts should equal Box 8 plus anything unpaid from earlier periods.

For a deeper check, IRAS provides the GST Assisted Self-help Kit, known as ASK, for reviewing past returns ^[2] .

File and pay

Both the return and the payment are due one month after the end of the accounting period covered by the return ^[3] .

Businesses on a GIRO plan for GST have the deduction made on the 15th day of the month after the payment due date. A business on a special accounting period files within one month of the end of that period. IRAS states that, because one month is a reasonable deadline, no extensions will be granted. A nil return must be filed even if there was no business activity ^[3] .

Get the client’s approval of the figures in writing before you submit, and save the acknowledgement page afterwards. All dates are in Singapore tax deadlines.

If the return is late

Failing to file by the due date is an offence, and IRAS sets out what it may do ^[4] :

• Issue an estimated Notice of Assessment and impose a 5% late payment penalty on the estimated tax. The business must then file immediately and pay the estimated tax with the penalty; the estimate is revised once the actual liability is declared.
• Impose a late submission penalty: $200 immediately when the return is not filed by the due date, and a further $200 for every completed month the return remains outstanding, to a maximum of $10,000 for each return.
• Issue a Notice to Attend Court or a summons to the business or the people responsible for running it, including a sole proprietor, partner, or director.

Paying the penalty does not end the matter. IRAS notes that legal action may still be taken if the outstanding return is not filed ^[4] .

Correcting errors

If a submitted GST F5 is wrong, the correction is made by filing a GST F7 ^[5] .

IRAS allows an administrative concession: you may adjust in the next GST F5 instead, if both of these are met ^[5] :

1. The net GST amount in error for all the affected accounting periods is not more than $3,000. Net GST in error is the difference between the additional output tax for Box 6 and the additional input tax for Box 7.
2. The total amount in error for the other boxes, in each affected period, is not more than 5% of the total value of supplies in Box 4 of the submitted return. Where no supplies were made in the period, the 5% is measured against taxable purchases in Box 5.

The concession does not cover pre-registration input tax claims in Box 12. If the only error is the revenue figure in Box 13, no adjustment is needed ^[5] .

Two further points from IRAS shape how quickly to act. Penalties of up to 200% of the tax owed may be imposed for errors, but no penalties are imposed if the errors are corrected within a year from the GST F5 filing deadline ^[2] . And a claim for GST overpaid should be made within five years from the end of the accounting period it relates to ^[5] .

Record each correction with the working papers: the period, the boxes affected, the amounts, and whether it went through an F7 or the next F5.

After filing

• Lock the period in the ledger.
• File the working papers: the F5 as submitted, the acknowledgement, the GST detail report, the reconciliation to the ledger, and the client’s approval. See workpapers and audit trail.
• At year end, agree the four returns to the GST accounts as part of the financial year end checklist.

Where ExpenseFlow fits

Most of IRAS’s error list is about purchases, and purchases are coded when they are captured. ExpenseFlow reads each line of a bill or receipt and assigns GST treatment using a Singapore rule set. It flags blocked input tax, such as the disallowed categories above, for review instead of letting it through as a claim, and it flags documents where a valid tax invoice is required, a missing or invalid tax code, and a cross-border purchase coded as domestic. It extracts the supplier’s GST registration number from the document and shows it; it does not validate the number. Each item waits in a review queue until a person approves it, then syncs to Xero or QuickBooks Online.

ExpenseFlow does not prepare or submit the GST F5 or F7 and does not make payments to IRAS.